|MadSci Network: Immunology|
Unfortunately, the answer to that question is not known. There are many theories depending on what the specific disease is, but there is no agreement from the experts in the field on one direct cause.
The term "autoimmune disease" refers to a varied group of more than 80 serious, chronic illnesses that involve almost every human organ system. It includes diseases of the nervous, gastrointestinal, and endocrine systems as well as skin and other connective tissues, eyes, blood, and blood vessel. In all of these diseases, the underlying problem is similar--the body's immune system becomes misdirected, attacking the very organs it was designed to protect.
For reasons we do not understand, about 75 percent of autoimmune diseases occur in women, most frequently during the childbearing years. Hormones are thought to play a role, because some autoimmune illnesses occur more frequently after menopause, others suddenly improve during pregnancy, with flare-ups occurring after delivery, while still others will get worse during pregnancy.
Autoimmune diseases also seem to have a genetic component, but, mysteriously, they can cluster in families as different illnesses. For example, a mother may have lupus erythematosus; her daughter, diabetes; her grandmother, rheumatoid arthritis. Research is shedding light on genetic as well as hormonal and environmental risk factors that contribute to the causes of these diseases.
Most of this was taken from the American Autoimmune Related Diseases Association website ( http://www.aarda.org). Check it out!
Autoimmune diseases remain among the most poorly understood and poorly recognized of any category of illnesses. Individual diseases range from the benign to the severe. Symptoms vary widely, notably from one illness to another, but even within the same disease. And because the diseases affect multiple body systems, their symptoms are often misleading, which hinders accurate diagnosis.
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